1. Field of the Invention
This invention relates to a conveyor system having zone control modules which can detect product on an attached conveyor. More specifically, the invention relates to a zone control module which can be programmed with specific features and operational criteria by various hard wired or wireless devices. Additionally, the invention relates to a conveyor control system that can have several interconnected zone control modules which can pass operational information to one another using a simplified communications protocol, and to an interface which translates the simplified protocol to a standard communications network protocol that can communicate with a standard PC-based or networked computer environment.
2. Description of the Related Art
Conveyor control systems typically include one or more “zone” control modules which let a controller for the conveyor system detect the status (i.e. location) of objects being conveyed on the system. An example of such a system is disclosed in U.S. Pat. No. 6,302,266, issued Oct. 16, 2001, which discloses a conveyor system comprising a series of rollers rotatably mounted to a frame. The rollers are organized into roller “zones” in which the rollers in a zone operate in concert. A continuous-loop drive belt passes beneath the rollers, and is selectively brought into contact with a selected roller zone by a pneumatic actuator which, when actuated, extends to abut the belt with a selected number of rollers, and, when retracted, removes the abutment of the belt with the rollers. A plurality of interconnected zone control modules and photo-electric sensing devices (often referred to as “photo-eyes”) are mounted in a suitable fashion at regular intervals to the frame, with each zone control module and photo-eye operably associated with a specific zone. Each zone control module incorporates a solenoid-driven pneumatic valve for delivering pressurized air to the pneumatic actuator serving that module. A signal from the photo-eye, indicating the presence or absence of a package on the associated zone, will activate the zone control module and the pneumatic actuator for a specific zone.
One problem with the prior art network or PC-based conveyor systems is that they are typically server-based systems, where every zone control module must be separately connected to the server. Furthermore, each zone control module must have a unique ID, which must be reprogrammed into the system control program when the zone control module is replaced, or new modules added. Wiring must typically be run to each zone control module, and then bussed to a controller which must decipher which zone the information came from.
This problem has been addressed by providing conveyor control modules with microprocessors which can deliver additional information via standard networking/communication protocols (i.e. RS-232). However, there remain problems with the prior art conveyor systems. These prior art devices require accurate positioning information to determine the zone control module's location in a series of modules. Often, standard networking protocols require a unique zone control module ID for each module, making replacement and repair to conveyor control systems difficult.